Retrofit Package Uses Sails, Solar, and Batteries for CII Compliance

emissions retrofit approach
Vertom's Anna has begun the conversion process fitting two rigid sails in 2022 (Vertom)

Published Jun 27, 2023 6:47 PM by The Maritime Executive

As shipowners look for solutions to meet the emerging environmental regulations, a new integrated approach for a green retrofit package is being presented that would permit in-service vessels to meet CO2 reduction targets in compliance with CII. The solution, which was awarded an Approval in Principle (AiP) from the Italian classification society RINA, incorporates rigid sails, solar panels, batteries, optimized weather-routing, and a smart decision support system to dramatically reduce emissions of an existing Newcastlemax bulk carrier.

Naval architects Aurelia worked in partnership with Econowind, Wattlab, and Vertom to design a two-step approach that would make it possible to extend the economic life of an existing 203,000 dwt bulk carrier. For their research, they studied a 984-foot bulker with an operating range of 24,500 nautical miles. They studied what would be needed to comply with the CII index based on five annual sailings between Brazil and China.

The team proposed a two-step investment process for shipowners seeking to comply with the CII index. The first phase would be done in 2023 and involves the installation of Solar Flatrack technology, a modular solar energy system, that comprises movable, stackable, thin plates with integrated solar panels and inverters and acts as a sustainable generator. In addition, they call for adding batteries and using operation planning software developed by Hydrographic and Marine Consultants.

The combination of these currently available technologies aims to reduce the hours in service of the auxiliary engines. Any surplus energy not consumed by the vessel the designers report would be used to charge the battery bank. This first stage of the retrofit of the auxiliary engine reduces the total CO2 emissions by 6.1 percent, or 3305 tons, and marine gasoil (MGO) fuel of the auxiliary engine by 97.5 percent.

The second stage of investment, required by 2025, includes the installation of six rigid, 100-foot-high sails to provide supporting wind propulsion, along with switching from fossil to biofuels. The added wind propulsion provides power to the vessel and lowers the load of the main engine, thereby reducing fuel consumption. With the use of biofuels to further lower emissions, the team reports this investment stage would reduce CO2 emissions by 10.3 percent or 5560 tons of CO2 per year.

Belgian shipping company Vertom also joined the retrofit project and in 2022 started the retrofit process. The company’s general cargo ship Anna (5,000 dwt) was fitted with two 52-foot Econowind VentiFoils for wind-assisted propulsion. This year, they are testing the Solar Flatrack panels and plan to begin installing them on cargo vessels in 2023.

According to Aurelia, their retrofit package solution can be applied to almost any kind of vessel and it will not interfere with operational aspects, such as loading and offloading cargo. They believe by incorporating these currently available technologies, it is currently possible to achieve practical, viable solutions to the challenges emerging from the IMO’s Carbon Intensity Index and other environmental regulations.